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pidns_tests.c
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pidns_tests.c
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#define _GNU_SOURCE
#include "syscall.h"
#include "types.h"
#include "user.h"
#include "tester.h"
#define ARRAY_SIZE(array) (sizeof(array) / sizeof(array[0]))
#define CLONE_NEWPID 2
#define NULL 0
typedef signed int pid_t;
typedef signed int size_t;
void assert_msg(int r, const char *msg) {
if (r) {
return;
}
printf(stderr, "%s\n", (char *)msg);
exit(1);
}
static void write_all(int fd, unsigned char *buf, size_t len) {
size_t bytes_read = 0;
while (bytes_read < len) {
size_t ret =
check(write(fd, &buf[bytes_read], len - bytes_read), "failed to write");
bytes_read += ret;
}
}
static void read_all(int fd, unsigned char *buf, size_t len) {
size_t bytes_read = 0;
while (bytes_read < len) {
size_t ret =
check(read(fd, &buf[bytes_read], len - bytes_read), "failed to read");
bytes_read += ret;
}
}
/* static void wait_for(int fd, char *s) { */
/* char buf[0x80]; */
/* size_t len = strlen(s); */
/* if (len + 1 >= sizeof(buf)) { */
/* exit(1); */
/* } */
/* int ret = check(read(fd, buf, len + 1), "read"); */
/* if (ret != len + 1) { */
/* exit(1); */
/* } */
/* if (strcmp(s, buf) != 0) */
/* exit(1); */
/* } */
typedef int (*test_func_t)(void);
/* Verify that we can create process in child pid namespace
- Unshare pid ns
- Fork
- Child process fork
- Verify that the pid is correct
*/
int test_simple_pidns_fork() {
check(unshare(CLONE_NEWPID), "failed to unshare");
int ret = check(fork(), "failed to fork");
// child
if (ret == 0) {
assert_msg(getpid() == 1, "pid not equal to 1");
ret = check(fork(), "failed to fork 2");
// child
if (ret == 0) {
assert_msg(getpid() == 2, "pid not equal to 2");
exit(0);
}
int status = child_exit_status(ret);
assert_msg(status == 0, "child process failed");
exit(0);
}
// flaky test because pid can recycle. However strictly speaking pid should be
// increasing
assert_msg(getpid() < ret, "wrong pid");
int status = child_exit_status(ret);
assert_msg(status == 0, "child process failed");
return 0;
}
/* Verify simple pid namespace works
- Unshare pid ns
- Fork
- Verify pid is correct from parent and child views
*/
int test_simple_pidns() {
check(unshare(CLONE_NEWPID), "failed to unshare");
int ret = check(fork(), "failed to fork");
// child
if (ret == 0) {
assert_msg(getpid() == 1, "pid not equal to 1");
exit(0);
}
// flaky test because pid can recycle. However strictly speaking pid should be
// increasing
assert_msg(getpid() < ret, "wrong pid");
int status = child_exit_status(ret);
assert_msg(status == 0, "child process failed");
return 0;
}
/* Verify that we can create a pid namespace within pid namespace
- Unshare pid ns
- Fork
- Child process unshare pid ns
- Child process fork
- Verify pid is correct from parent and children views
*/
int test_nested_pidns_create() {
check(unshare(CLONE_NEWPID), "failed to unshare");
int ret = check(fork(), "failed to fork");
if (ret == 0) {
assert_msg(getpid() == 1, "pid not equal to 1");
exit(test_simple_pidns_fork());
}
int status = child_exit_status(ret);
assert_msg(status == 0, "child process failed");
return 0;
}
/* support function to create multiple children */
void create_children(int n, pid_t *child_pids, test_func_t func) {
for (int i = 0; i < n; i++) {
int ret = check(fork(), "failed to fork in create_children");
if (ret == 0) {
// child
exit(func());
}
if (child_pids) {
child_pids[i] = ret;
}
}
}
/* support function to wait on multiple children */
void reap_children(int n, pid_t *child_pids) {
int count = 0;
int wstatus = 0;
while (count < n) {
int pid = check(wait(&wstatus), "failed to wait()");
// if we don't verify the child pids just count them
if (!child_pids) {
count++;
continue;
}
for (int i = 0; i < n; i++) {
if (child_pids[i] == pid) {
count++;
assert_msg(WEXITSTATUS(wstatus) == 0, "exit code is not 0");
break;
}
}
}
}
/* support function to busy wait forever */
int loop_forever() {
while (1) {
}
return 0;
}
/* support function to busy wait about 1 secound */
int sleep_1s() {
// TODO: find a better way to sync the destruction
sleep(10);
return 0;
}
/* Verify that when non init process in the namespace dies it’s children are reaped by init pid within the namespace
- Unshare pid ns
- Fork (1)
- Fork (2)
- Child (2) process fork (3)
- Child (2) process fork (4)
- Child (2) process dies
- Grandchildren (3) & (4) dies
- Verify that wait returns with correct pids for (2) and grandchildren (3) & (4)
*/
int test_children_reaped_by_nspid1() {
check(unshare(CLONE_NEWPID), "failed to unshare");
int ret = check(fork(), "failed to fork");
if (ret == 0) {
pid_t child_pids[2];
int fd[2];
check(pipe(fd), "failed to create pipes");
// child is pid 1
assert_msg(getpid() == 1, "pid not equal to 1");
// create pid 2
int ret = check(fork(), "failed to fork2");
if (ret == 0) {
create_children(ARRAY_SIZE(child_pids), child_pids, sleep_1s);
write_all(fd[1], (void *)child_pids, sizeof(child_pids));
// cleanup fds
close(fd[0]);
close(fd[1]);
// kill pid 2
exit(0);
}
read_all(fd[0], (void *)child_pids, sizeof(child_pids));
// cleanup fds
close(fd[0]);
close(fd[1]);
// reap child pids
reap_children(ARRAY_SIZE(child_pids), child_pids);
exit(0);
}
int status = child_exit_status(ret);
assert_msg(status == 0, "child process failed");
return 0;
}
/*Verify that when init process within the namespace dies all children are killed
- Unshare pid ns
- Fork (1)
- Child process fork (2)
- Child process fork (3)
- Child process dies
- Verify that (2) & (3) are dead
*/
int test_all_children_kill_when_nspid1_dies() {
check(unshare(CLONE_NEWPID), "failed to unshare");
int ret = check(fork(), "failed to fork");
if (ret == 0) {
pid_t child_pids[2];
// child is pid 1
assert_msg(getpid() == 1, "pid not equal to 1");
//create_children(2, NULL, loop_forever);
create_children(ARRAY_SIZE(child_pids), child_pids, loop_forever);
// pid 1 exits
exit(0);
}
// Note: I'm supposed to only wait on one process sincew the other proccesses
// are reaped by the kernel (which is inconsistent and wierd).
// This test will fail on an infinite loop
int status = child_exit_status(ret);
assert_msg(status == 0, "child process failed");
return 0;
}
/* Verify that calling unshare -> fork -> (child dies) -> fork fails
- Unshare pid ns
- Fork (1)
- Child (1) dies
- Fork fails
*/
int test_calling_fork_after_nspid1_dies_fails() {
check(unshare(CLONE_NEWPID), "failed to unshare");
int ret = check(fork(), "failed to fork");
if (ret == 0) {
// child is pid 1
assert_msg(getpid() == 1, "pid not equal to 1");
// pid 1 exits
exit(0);
}
// make sure it's dead
int status = child_exit_status(ret);
assert_msg(status == 0, "child process failed");
ret = fork();
assert_msg(ret < 0, "fork didn't fail as expected");
return 0;
}
int MAX_RECURSION = 4;
/* Verify that there’s recursive limit to nesting pid namespace
- Unshare
- Fork (1)
- Unshare (1)
- Fork (2)
- Unshare (2)
- Fork (3)
- Unshare (3)
- Verify that will fail Fork (4)
*/
int _test_unshare_recrusive_limit(int count) {
if (count == 0) {
assert_msg(unshare(CLONE_NEWPID) < 0, "unshare didn't fail as expected");
return 0;
}
check(unshare(CLONE_NEWPID), "failed to unshare");
int ret = check(fork(), "failed to fork");
if (ret == 0) {
// child is pid 1
assert_msg(getpid() == 1, "pid not equal to 1");
_test_unshare_recrusive_limit(count - 1);
// pid 1 exits
exit(0);
}
// make sure it's dead
int status = child_exit_status(ret);
assert_msg(status == 0, "child process failed");
return 0;
}
int test_unshare_recrusive_limit() {
// there's an init namespace so we start counting from 1
_test_unshare_recrusive_limit(MAX_RECURSION-1);
return 0;
}
/* Verify that a process can call unshare PID only once
- Unshare
- Unshare
- Verify the last Unshare failed
*/
int unshare_twice() {
// first call should succeed
int ret = unshare(CLONE_NEWPID);
if (ret < 0) {
return 1;
}
// second call should fail
ret = unshare(CLONE_NEWPID);
if (ret < 0) {
return 0;
}
return 1;
}
int test_calling_fork_twice_after_unshare() {
check(unshare(CLONE_NEWPID), "failed to unshare");
int ret = check(fork(), "failed to fork");
if (ret == 0) {
// child is pid 1
assert_msg(getpid() == 1, "pid not equal to 1");
sleep(5); /*Changed to 5 to remove a zombie process appearing*/
// pid 1 exits
exit(0);
}
int ret2 = check(fork(), "failed to fork");
if (ret2 == 0) {
// child is pid 2
assert_msg(getpid() == 2, "pid not equal to 2");
// pid 1 exits
exit(0);
}
// make sure it's dead
int status = child_exit_status(ret2);
assert_msg(status == 0, "child process failed");
// make sure it's dead
status = child_exit_status(ret);
assert_msg(status == 0, "child process failed");
return 0;
}
int main() {
printf(stderr, "Running all pidns tests\n");
run_test(unshare_twice, "unshare_twice");
run_test(test_simple_pidns, "test_simple_pidns");
run_test(test_simple_pidns_fork, "test_simple_pidns_fork");
run_test(test_nested_pidns_create, "test_nested_pidns_create");
run_test(test_children_reaped_by_nspid1, "test_children_reaped_by_nspid1");
run_test(test_all_children_kill_when_nspid1_dies, "test_all_children_kill_when_nspid1_dies");
run_test(test_calling_fork_twice_after_unshare, "test_calling_fork_twice_after_unshare");
run_test(test_calling_fork_after_nspid1_dies_fails, "test_calling_fork_after_nspid1_dies_fails");
run_test(test_unshare_recrusive_limit, "test_unshare_recrusive_limit");
if (testsPassed == 0) {
printf(stderr, "Pidns tests passed successfully\n");
exit(0);
}
else {
printf(stderr, "Pidns tests failed to pass\n");
exit(1);
}
}